<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="root"></div>
    <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
    <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
    <script type="text/babel">
        let random = function(num){
            return parseInt(Math.random() * num);
        }
        class Card extends React.Component{
            constructor(props){
                super(props);
            }
            render(){
                let style = {
                    width:"150px",
                    height:"150px",
                    backgroundColor:`rgb(${random(256)},${random(256)},${random(256)})`,
                    color:`rgb(${random(256)},${random(256)},${random(256)})`
                };
                return <div style={style}>
                    {this.props.children}
                </div>
            }
        }
        class Parent extends React.Component{
            constructor(props){
                super(props);
            }
            render(){
                let letters = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U"];
                return <div>
                    <h1>字母卡片</h1>
                    {letters.map(item => <Card  key={item}>{item}</Card>)}
                </div>
            }
        }

        ReactDOM.createRoot(document.getElementById("root")).render(<Parent />);
    </script>
</body>
</html>